In the insulation field it was well known to provide gypsum and foamed gypsum for insulation purposes, such as is disclosed in the following U.S. patents:
______________________________________ Crepeau et al. 4,240,839 Pratt et al. 3,563,777 Riddell et al. 2,731,377 Dixon et al. 2,862,829 Dickey et al. 2,556,031 Chappell 2,593,008 Mollo 2,602,759 Hoffman 2,913,346 Healey 4,133,638 Yano 3,974,024 Selden 2,915,301 Ergene 3,758,319 Lange et al. 3,926,650 Knowlton 1,798,609 Foster 3,526,685 Bragg et al. 3,719,513 Rothfelder et al. 3,839,059 Upson 1,772,648 Flake 4,229,223 Armstrong 2,664,406 Sucetti 2,921,862 Taylor 2,979,415 ______________________________________
In the filter field, to which the present invention pertains, generally a Hopcolite filter was employed for the removal of carbon monoxide. Hopcolite is a mixture of silver permanganate, copper oxide and nickel oxide. This prior art product was disadvantageous for several reasons, including the fact that it generated heat in use, was relatively expensive and contained substantial heavy metal compounds.
Now there is provided by the present invention a CO filter which is highly effective, non-toxic, non-flammable, light weight, non-settling, does not heat on use, and relatively low cost.
It is therefore a principal object of the present invention to provide a novel filter composition.
It is another object of the present invention to provide a filter composition useful in human user systems such as for example face mask filter and cigarette filter.
It is still a further object of the present invention to provide a filter system as aforesaid which in a broad sense simulates the filter activity of human lungs.